fn main() {
    let x = 5;
    println!("the value of x is: {}", x);

   //  x = 6; // error 变量不能再次赋值

  // let obj = {a:1};// error struct literal body without pathrustc 不知道这个是啥子错

   println!("the value of obj is {}",false);

   let mut y = 5;
   y = 6;
   println!("the value of y is {}", y);

   const THREE_HOURS_IN_SECONDS_1: i32 = 60 * 60 * 3;
   const THREE_HOURS_IN_SECONDS_2: i32 = 123456;
   println!("three hours is {} s,---{}", THREE_HOURS_IN_SECONDS_1,THREE_HOURS_IN_SECONDS_2)
   // 可变变量 不能修改类型
   // 隐藏可以修改变量的类型
}

